Accessing my internal system using

ACP provides a neat feature where you can get a no-ip address which allows you to access your observatory using a unique name (mine is

I have the problem of not being able to access my observatory using from within my home network. Access works fine from outside the home, but within your LAN you have to address the observatory as 192.168.x.x. This leads to awkward coding of web pages/twiddlers, bookmarks that don’t always work, etc.

1) Supposedly, buying a fancier router that supports NAT loopback can resolve this issue. I was preparing to do this; the model I was looking at costs about $130. I did not test this out since solution 2 worked.

2) Change the etc/hosts file on your home computer. This file resolves name addresses before the system goes out to the Internet for DNS resolution.

In my case, the observatory computer hosts the ACP server. My home computer is where I mostly work from. I want my twiddlers, and my blog entries, to use to access a couple of web pages I have created. These do things like show current weather, forecasts, and operate the power controller in the observatory.

The hosts file is located in c:\Windows\system32\drivers\etc. I added the line
There should be no leading spaces. A single space or tab separates the IP address and the name.

1) When you edit the hosts file, Windows will not let you save it back in the etc directory. Save it into your Documents directory, remove the .txt extension Notepad insists on adding, then COPY (don’t move) the file to etc.

2) In theory the system immediately starts using the new hosts file. To make sure, use a cmd.exe window and enter “ipconfig /flushdns” to clear the cached entries.

3) test by pinging your domain name.    “ping”
a) If the host file is not active, you will see your remote IP address (like
b) If it works, you will see the local address

4) You may need to restart your browser? I did not need to, but several net posts indicated this was necessary. Firefox in particular may cache DNS entries.

5) One system continued to have problems (a laptop with Windows 8.1). I found that I needed to add permissions for Users to the hosts file (Properties/Security on file hosts). It would only let me add a particular setting, but that worked fine.


More Darkness Readings

Went out before the moon came up and got some readings in different areas nearby. The idea was to verify whether the map showing light levels is correct or accurate. In addition, to check the calibration of the SQM-L meter versus the iPhone app.

Light Measurements at three locations near Casa Grande.

Light Measurements at three locations near Casa Grande.

The lower point (6.1 Bortle) is just into an Indian reservation. These readings were taken between 9:00-9:30PM, 25 degrees C.

The upper point (5.8 Bortle) is on the other side of some mountains nearby; I think to the north of this location is another reservation. Readings taken between 10:00-10:30 PM.

The readings at the middle point are my backyard, between 10:30-10:45. The moon rose shortly after.


1) The map’s darker areas are in fact measurably slightly darker. The 6.1 site in particular was noticeably darker.

2) My area just has too many neighbors with outside lights on!

3) The iPhone app clearly has much more variability than the SQM-L. Perhaps if I take about 10-15 readings and average things work out OK. It also looks like I need to add about .15 to the iPhone value, although this difference changes with the different reading values; a greater difference is shown at the 6.1 value than the 5.65.